An assessment of the problems that are presented by non-native and introduced species in maintaining native species and natural systems. Divided into two major sections, the study covers representative ecosystems in Pima County as well as representative species that have a negative impact on native species.

Provides a brief summary of a compilation of resource investigations that have been submitted so far, to help develop the SDCP within the watershed planning area of the Upper Santa Cruz Valley.

A companion to the study issued on July 5, 2000 entitled 'Cactus Ferruginous Pygmy-Owl Investigations in Pima County.' The major objective was to determine whether pygmy-owls chose nest sites or perch trees with characteristics that differ from other available sites within a nesting territory.

Evaluates the conservation significance of county-owned properties in Avra Valley, specifically with regard to Priority Vulnerable Species and the Sonoran Desert Conservation Plan.